ui/gfx/generic_shared_memory_id.h

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef UI_GFX_GENERIC_SHARED_MEMORY_ID_H_
   6 #define UI_GFX_GENERIC_SHARED_MEMORY_ID_H_
   7
   8 #include "base/trace_event/memory_allocator_dump.h"
   9 #include "ui/gfx/gfx_export.h"
  10
  11 namespace gfx {
  12
  13 // Defines an ID type which is used across all types of shared memory
  14 // allocations in content/. This ID type is in ui/gfx, as components outside
  15 // content/ may need to hold an ID (but should not generate one).
  16 class GFX_EXPORT GenericSharedMemoryId {
  17  public:
  18   int id;
  19
  20   // Invalid ID is -1 to match semantics of base::StaticAtomicSequenceNumber.
  21   GenericSharedMemoryId() : id(-1) {}
  22   explicit GenericSharedMemoryId(int id) : id(id) {}
  23   GenericSharedMemoryId(const GenericSharedMemoryId& other) = default;
  24   GenericSharedMemoryId& operator=(const GenericSharedMemoryId& other) =
  25       default;
  26
  27   bool operator==(const GenericSharedMemoryId& other) const {
  28     return id == other.id;
  29   }
  30
  31   bool operator<(const GenericSharedMemoryId& other) const {
  32     return id < other.id;
  33   }
  34 };
  35
  36 // Generates GUID which can be used to trace shared memory using its
  37 // GenericSharedMemoryId.
  38 GFX_EXPORT base::trace_event::MemoryAllocatorDumpGuid
  39 GetGenericSharedMemoryGUIDForTracing(
  40     uint64_t tracing_process_id,
  41     GenericSharedMemoryId generic_shared_memory_id);
  42
  43 }  // namespace gfx
  44
  45 namespace BASE_HASH_NAMESPACE {
  46
  47 template <>
  48 struct hash<gfx::GenericSharedMemoryId> {
  49   size_t operator()(gfx::GenericSharedMemoryId key) const {
  50     return BASE_HASH_NAMESPACE::hash<int>()(key.id);
  51   }
  52 };
  53
  54 template <typename Second>
  55 struct hash<std::pair<gfx::GenericSharedMemoryId, Second>> {
  56   size_t operator()(
  57       const std::pair<gfx::GenericSharedMemoryId, Second>& pair) const {
  58     return base::HashPair(pair.first.id, pair.second);
  59   }
  60 };
  61
  62 }  // namespace BASE_HASH_NAMESPACE
  63
  64 #endif  // UI_GFX_GENERIC_SHARED_MEMORY_ID_H_